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CITY COMPOST FOR MOUNTAIN AGRICULTURE

Mrs Almitra H Patel, MS MIT USA, Member Supreme Court Committee for Solid Waste Management, 50 Kothnur, Bagalur Rd, Bangalore 560077.

Nov 2003

Organic farming needs organic inputs. India’s carbon-rich soils made the Green Revolution possible, but today’s declining yields from organic-poor soils face a national shortfall of 6 million tons a year of organic manures for agriculture. This shortfall can be met by composting our biodegradable city wastes. This is now the law of the land. Household wastes are unusable and unwanted because we throw out all our wastes mixed together. Plastic carrybags in fields reduce both germination and rainfall absorption. The solution : DO NOT MIX WASTES ! Collect “wet” food wastes door-to-door for composting and recycle “dry” wastes. Road-sweeping dust, drain silt and debris, which must never be collected in the same trip as other waste, can be usefully used for plinths or land reclamation.

Thin plastics, shredded, are best used in tar roads. 8% by weight in bitumen gives far longer life and less cracking, so the Border Roads Organisation should adopt this practice everywhere. PET bottles are now recycled. Broken glass must be kept out of wastes for composting. Discarded tube-lights can be revived or used as sleeves for copper tubing in solar-heaters for added efficiency.

Waste is best composted, as-is, in wind-rows, which heat up faster when sprayed with compost-starter biocultures. Heat kills germs and weed seeds and reduces heap volumes by 50%. Sanitising of waste with good biocultures reduces flies and smell within 24 hours. Stabilising of waste needs 45-60 days for conversion to a humus-rich product. Cities must sieve and use this for their own parks and gardens. Sieving is the costliest stage of composting, so the better the segregation of waste, the cheaper and easier it is to produce and sell it, improving both farm prosperity and city cleanliness.

Marketing city compost is difficult as farmers want it at farmyard manure prices, although it is four times more effective than FYM. Compost’s increased water-holding capacity reduces crop-watering frequency, strengthens roots and reduces the need for pesticides. The best long-term yields come through Integrated Plant Nutrient Management : the combined use of organic manures with chemical fertilizers. IPNM totally protects soils from steep declines in yield observed with NPK alone and is ideal for Indian agriculture, being cost-efficient and affordable. Replacing 50% of chemical fertilizers with compost gives better yields at equal cost. Organic-certified farmers need reliable composts from well-segregated pesticide-free market-wastes.

Stabilised city wastes can be used unsieved to reclaim degraded and saline soils, cover mining overburden and eroded slopes and stabilize landslides.